At NASA Goddard Space Flight Center last month, Sen. Barbara A. Mikulski and space agency Administrator Charles Bolden stressed the importance of maintaining budget support for the James Webb Space Telescope, keeping it on track for a 2018 launch.

Sticking to that schedule is the job of the Webb telescope's project manager, Bill Ochs, who, from his office on the Greenbelt campus, oversees all of the moving parts slated to come together and be blasted into space in 41/2 years.

It's a complicated job, Ochs acknowledged, but since new development and spending plans were approved three years ago for the delayed and over-budget project, things have been running smoothly. That was helped when the project got its requested $627.6 million for 2013, despite the across-the-board federal cuts known as sequestration.

The Webb telescope will replace the aging Hubble Space Telescope and is designed to study the formation of the first stars and galaxies in infrared light, from a point in space nearly a million miles from Earth. Ochs sat down with The Baltimore Sun to discuss recent milestones in the telescope's construction and what's ahead.

Does the federal budget situation have any effect on day-to-day progress on the Webb project?

Every year since we've done our replan back in 2011, we have gotten the budget that we said we needed. [Mikulski] obviously is a big help with getting that for us. When we did our replan and came up with our new budget, the deal was a two-way street. Congress said, 'OK, we'll give James Webb another chance, and we'll give you this budget, but don't go a penny over.' Our end of the deal is we've got to do what we said we were going to do. For the last three years almost now, we've been doing that.

The final two of the telescope's four scientific instruments were recently delivered to Goddard. What are the challenges ahead?

Getting instruments delivered is always a big event because you're retiring some very large risks when you do that. To have instruments delivered and have them in-house five years prior to launch is huge. We're gearing up now for the next cryovac test [instruments are tested in a chamber designed to mimic the extreme cold and vacuum of space]. We're supposed to go into the chamber end of May-ish time frame. It's about a 90-day test, maybe a little bit more, so that will get us through the summer with the instruments.

How do you account for issues that come up along the way that affect the schedule and budget?

There is scheduled buffer all along. When I say [launch is scheduled for] October 2018, it's assuming that you've used all that schedule margin or buffer up. We fully anticipate using a good majority of it because we're doing too many firsts and a lot of stuff we're doing is really hard. When you're going through a spacecraft buildup, and especially an observatory like this, as a project manager you have three tools to mitigate risks. One is you can reduce requirements. In this phase we're going into testing, and you get to a point where you've tested, you're just about at the requirement you want to meet, [and you ask] "Well, is that good enough?" That's a question you have to ask your scientists. The next is just money. We have dollar reserves that can be used to fund things like a second shift on a schedule, overtime, I've got to go fix something that's not working, something just took longer than planned. The last thing you have is schedule reserve. I try all these other things first and we try to solve the problem. At some point, as hard as you try with that schedule, I'm going to need another month to get something done.

In a lot of cases, you don't know what the problem is going to be until it comes up. How do you prepare for that?

We have a risk management process and one of the jobs of the folks here is to think ahead — well, what could happen? We go through a process that says, "If this has a fairly high probability of happening, let's spend some of those reserve dollars now to mitigate that risk." That's a pretty robust system. It starts down at the lower levels, and if they can't solve the problem, it bumps its way up eventually to a project level. We meet on a weekly basis to discuss risks, any new ones that come into the system, and ensure that if I've got to be spending money to fix this and make sure that's not going to happen that we spend that money to do that. It's part of building a spacecraft. There's always, we call them, the unknown unknowns.

Budgets and schedules have both grown since the project's genesis. How do you know that won't happen again?

I'm very confident. When I came on board, my directive was to build a high-confidence schedule and budget, and that's what we did. People don't like the cost at times, but that wasn't our job to decide. Our job was to come up with what it was really going to cost. The final cost through operations is $8.8 billion. But it's $8 billion to launch, and Congress said, "If you go a penny over that, you're in a lot of trouble." We put the right conservatism into the schedule to make sure we had the buffers in place to avoid problems. The simplest spacecraft is still hard. This is probably the most complex spacecraft NASA has ever built, which makes it even harder. So, you want to be conservative in what you do. It's very challenging, but I think we have all the right tools to meet our commitments we made to our stakeholders.